The present invention provides advances in corneal laser keratotomy which greatly reduce the risk of major operative and long term complications.
Heretofore, laser keratotomy procedures have often involved relatively extensive procedures with substantial probability of complications. One such procedure, identified as LASIK (an acronym for Laser In Situ Keratomileusis), involves the cutting of a flap over a wide area of the cornea. Because corneal tissue does not heal, when such flap is replaced in position, only an outside layer of ephithelial cells grows over the interface to provide the only means of holding the flap in position. Such layer of cells is only about 6 or 7 cells thick and is the only support that holds the flap in position. In the event that the patient's eye is impacted, rubbed, etc., such flap may break loose, as occurs relatively frequently, requiring further and often serious procedures.
In accordance with the present invention, a slit is made with a sharp blade into the anterior cornea to a predetermined depth. A pocket is defined by separating corneal lamellae by employing a blunt dissector manipulated by the surgeon to define either a straight pocket, with linear edges, or by utilizing a curved dissector, to define an arcuate pocket or arcuate segments, in accordance with the particular needs of a patient.
The pocket in the cornea may also be defined by an automated keratome having a sharp cutting blade or trephine, vibrating at very high rates.
A spatula or glide is inserted into the pocket thus formed. The spatula has thereon means for defining the configuration of laser ablation of the corneal tissue. Reflective or mirror areas on the spatula reflect the laser beam onto the anterior wall of the pocket. In using a spatula with openings defined therein the laser beam passes through such opening or openings for ablation of the posterior wall of the pocket.
The reflective areas or openings may be defined on or in the dissector or the blade of the keratome which remains in the pocket after the pocket is cut. The dissector or keratome blade remains in the pocket during laser ablation.
After the ablation of corneal tissue, the blade or spatula is removed from the pocket, whereupon the walls of the pocket are urged together by normal pressure in the eye, with resultant change in the configuration of the cornea interior surface.